DESCRIPTION: (Applicant's Abstract) Diabetic macular edema, or thickening of the retina, is a common cause of visual loss in working age Americans. The Early Treatment Diabetic. Retinopathy Study (ETDRS) showed that vision can be preserved by prompt application of laser photocoagulation to areas of thickened retina. However, although laser treatment for clinically significant macular edema has been demonstrated to reduce the risk of visual loss, it does not prevent visual loss in all treated patients. Only a 50% reduction in risk of visual loss as a result of prompt photocoagulation was seen in the ETDRS. The National Eye Institute (NEI), in its Vision Research: a National Plan 1999-2003, has identified the understanding of the pathogenesis of diabetic retinopathy and development of strategies for improved treatment of diabetic retinopathy as program objectives. Using our unique technology, developed under the auspices of the NEI, for measuring the retinal thickness at the posterior pole objectively and precisely, we collected detailed data on individuals with clinically significant macular edema. These data include objectively measured pre- and post-laser treatment maps of the retinal thickness. In addition, we have collected data to document the location of treatment spots and have detailed gradings of retinal pathology from stereo fundus photographs. We propose to extend the analysis performed under the support of the previous grant and subject these data to image processing to link the information on location of laser treatment, pathology, and objectively measured retinal thickness before and after treatment. Parameters to describe areas of significantly thickened retina, changes in retinal thickness after treatment, and distance from treatment spots and retinal pathology will be derived. Statistical analysis of risk factors for persistent or worsening of retinal thickness will be carried out, using methods to take into account the spatial correlation of these map-linked data. These analyses will help to identify factors contributing to favorable outcomes of laser treatment for macular edema, and may suggest hypotheses for altering treatment strategies that can be tested in future studies.